The present invention relates to a new and improved flat panel heater assembly for use in a corrosive environment and a method of manufacturing the heater assembly.
Heater assemblies are well known for use in a corrosive environment such as in electroplating or industrial dipping where acid baths and other corrosive fluids are utilized. These heater assemblies come in a wide variety of configurations, such as that disclosed in the Sakai U.S. Pat. No. 4,429,215 entitled Planar Heat Generator. The known planar heater assemblies suffer from the disadvantage that they are not readily and cost-effectively manufacturable, and due to the fact that many are not adequately sealed, they are subject to the corrosive effects of the hostile environment in which they may be located.
The panel heater of the present invention is particularly adapted for use in hostile wet chemistry environments such as heating a bath of acid or other corrosive fluid. The present heater is adapted to be directly inserted into the acid bath to effect heating thereof. The heater assembly is constructed and encapsulated with a fluoropolymer material which effectively seals the heating element and prevents the corrosive environment, such as the acid, from coming in contact therewith. If the corrosive environment or acid were to come in contact with the heating element, the heating element would fail. The encapsulation of the heater assembly to prevent the penetration of the corrosive environment into the heater assembly is critical. Some of the prior art attempts to eliminate the contact between the heating element and the corrosive environment by physically locating the heater element outside of the corrosive environment. For example, it is known to attach a flat planar heating element to the outside of a container which contains the acid bath and then heat the container and the acid therein. While this construction eliminates contact between the heater element and the corrosive environment, it does not provide for the most efficient transfer of heat to the acid bath.